http://nikonrumors.com/2016/01/18/how-to-reset-a-nikon-dslr-to-factory-default-settings.aspx
https://support.nikonusa.com/app/answers/detail/a_id/17395/session/L3RpbWUvMTQ1MzE1NjE2Ni9zaWQvaGxJaUVTR20=
Two Button reset
It is possible to quickly reset many of the shooting settings to their default values by simply holding two buttons simultaneously for two seconds (both buttons are marked with a green dot for reference). The buttons used for this reset differ depending on the camera model.
- Camera - Button 1 + Button 2
D40/D40X - Shooting information button + Playback zoom/Setting button
D50 - Shooting Mode button + Self timer button
D70 & D70s - BKT Button + Metering mode button
D90 & D80 - +/- Exposure Compensation button + AF Mode button
D600, D610 - +/- Exposure Compensation button + Thumbnail button
D100 - Flash mode button + BKT Button
D810(A), D800(E), D700, D200, D300, D300S & D7000, D7100, D7200 - QUAL (image quality/Size) + +/- Exposure Compensation button
D5000 - Information button + Information edit button
D5100, D5200, D5300 - Menu button + Information button
D1 series - FUNC (function) button + Thumbnail button
D60 - Playback zoom in button + Active D-Lighting button
D2 & D3 Series, D4(S) - ISO button + White Balance button
